Interlocking system for railroads



Sept; 22, 1931. w. K. HOWE 1,824,149

INTERLOCKING SYSTEM FOR RAILROADS Filed Sept. 12, 1929 Tmusmamorv INVE TOR; 2

%ATTONEY BYZZLZQZMWMI Patented Sept. 22, 1931 SIGN SYSTEM' F :JIGNQR TO GENERiiL RAELWAY ji -Tina Illilff EAILRGADS Application filed September 12, 1829. Serial No. 392,140.

T his invention relates to power interlockin systems, and more particularly pertains C3 to indication means and devices for such systoms.

5 In power interlocking systems, it is desir able for reasons familiar to those skilled in the art, to provide means in the towertor indisting that the switch or signal controlled by a partic lar lever has iroperly operated or esponded, which indicating means is emated by the switch machine and track switch ointly, in manner, that the indicating relay indicates the position. and locked condition of the track switch, which relay is employed to actuate the associated indication latch mechanism.

it may happen that an improper or false indication will be given under a certain combination of circumstances in an indication system of the constant current or battery type as above described. F or example, when the operator moves a control lever to a new governin position, there is a short interval of time arter power is applied to. the switch machine during which the contacts asso- 5;: ciated with the switch machine for controlling the indication relay, remain closed and the indication relay is energized; and, it the operator should quickly return the control lever to its former governing position the in indication latch mechanism may be released,

even though the operation of the switch machine from its former position has been initiated. Under such conditions, it provisions are made so that the switch machine will automatically reverse and follow the movement of the control lever to itsoriginal position, no particularly unsafe condition re- .nlts; but, if the switch machine should fail to reverse due to the failure of parts, blow- .m ing of a fuse by excessive current occurring such quick reversal of the control lever, like, the inertia of the motor armature L the earing of the switch machine might och the track switch points and even partiaily move them. This contingency would safe because the control lever would one position, although the track s Hitch would be unlocked and partly moved. ii ith these considerations in mind, it is l in accordance with the present inprovide an electric lock actuated ve position when power is applied to the switch machine, with its locking mem- 3 er preventing a quick reversal of the conver while in such a position. Also, this c lock is to have an electrical construciich causes the locking member to be releasing, suiiiciently to assure that the vitch machine has come to rest after its circuit for the new governing position has broken, which time period the lockmember assumes an inactive position and permits the control lever to be returned to its former governing position, in which position the indication latch mechanism may be released, it t ne switch machine is still in a coresponding extreme position and locked;

' ens other objects, purposes and charc features otthe present invention be in part obvious and in part pointed out as the description of the invention pro- ;re sses.,

'ihe sin 'le I of the accompanying crawin repress is 1 a diagrammatic manone specific embocnnent of the present ini i, as applied to power operated switch its associated track switch, its con- *er and other devices pertaining thereith reference to the single figure of the a tracl: switch TS is shown as opsuitable switch machine SM which ably oi the type 'lesc'ribed in my 1.,"6 oated September 4', is switch machine SM has the usual mechanism for controlling the r: vitch TS and is operably controlled 0 a normal and a reverse control wire 5 and 6 respectively in conjunction with a common return wire C, in any suitable manner well known to those skilled in the art, one such control being disclosed in my above mentioned Patent No. 1,466,903.

The switch machine SM also has associated therewith a group of contacts included within a dotted rectangle designated PD which are known as point detector contacts. and are jointly controlled by the track switch TS and the switch machine SM. More specifically, the point detector contacts PD include an insulated block 7 which is controlled to either of two extreme positions in correspondence with the track switch TS when saidtrack switch is locked by its controlling switch machine SM. This insulating contact block 7 assumes an intermediate non-contacting position at any such time that the switch machine SM is in operation and the track switch TS is unlocked. Mounted upon the movable insulated contact block 7 are contacts 8 and 9 which make contact between their respective pairs of fixed contacts when in the normal or reverse extreme positions only.

A shunt contact 10, biased toward a contacting position, is actuated to a non-contacting position when the movable contact block 7 is in a normal extreme position; also, a similar shunt contact 11, biased toward a contacting position, is actuated to a non-contacting position when the movable contact block 7 is in a reverse extreme position. An example of an operating mechanism for such point detector contacts is disclosed in the patent to C. S. Bushnell, Patent No. 1,517,236 dated November 25, 1924, with the specific construetion of such point detector contacts including shunt contacts being formed in any suitable manner, such for example as shown in an application by J. C. Lindner Ser. No. 385,172 filed August 12, 1929.

Associated with the point detector contacts PD, there is a local transformer T, the primary of which is supplied with alternat ing current potential from a suitable alternating current source over atransmission line extending from an interlocking tower.

In the tower, a control lever L is provided, which is capable of assuming the usual full normal and full reverse positions indicated by the arrows N and R respectively as they appear opposite the arrow on the control lever L. These full positions of the lever L are supplemented by normal and reverse indi-v cating positions designated by the arrows NI and RI respectively, which indicating positions are determined by an indication latch mechanism IM conventionally shown as including an indication magnet 15 and a locking plunger 16. The movement of the lever L, from a full position to an indication position, operates a tappet bar 17 from a corresponding extreme position to a central position by means of a cam slot 18', for controlling the associated mechanical interlocking between levers in the usual well known manner.

The lever L governs the operation of the switch machine SM over normal and reverse operating wires 5 and 6 in conjunction with a common wire C by means of movable contact members 12 and .13. These movable contact members 12 and 13 together with movable contact member 14 make contact between certain pairs of fixed contacts when the lever L is in the positions N and N1, and make contact between certain other pairs oi fixed contacts when the lever L in the positions. R and RI. A fuse F is associated with the switch machine operating contacts to prevent excessive overloads.

Preferably, a suitable electric lever lock is employed with the lever L to prevent movement of said lever from its normal position N and its reverse position R when the detector track section associated with the switch TS is occupied, however, such a lock has been omitted to simplify the description of the present invention.

Associated with the indication latch mechanism TM is a SS relay having a local phase winding 20 and a line-phase winding 21, which windings operably control a contact 22 to either of two extreme positions depending upon the relative instantaneous polarity of the alternating current flowing in the two windings. This contact 22 assumes a deenergized neutral position when either or both the phase windings 20 and 21 are deenergized- The local phase winding 20 is con tinuously energized from the secondary of a local transformer T which receives its energy from the same alternating current source as the local transformer T at the switch TS. The line-phase winding 21 receives its energy over two line wires in accordance with the position of the point detector contacts PD at the track switch TS. The contact 22 of the SS relay operably controls the energization of the indication magnet 15 in conjunction with an energy saving contact which may beactuated to a contacting position by the control of a lever latch 24;, also in conjunction with certain contacts governed by the lever L.

The switch machine SM is operably controlled by power from a suitable battery BT or any other suitable source of electrical energy. The current, flowing from the positive terminal of this battery BT, passes through the windings. oi a power lock PL which actuates a locking member 25 to an active positnon when such current is flowing. The locking member 25 when in an inactive position as shown, allows the lever L to be moved in accordance with the various other locking devices, ofwhich the indication latch mechanism TM is shown. However, when the lever L has been moved to a new governing posi tion causing power current to flow so that the locking member is in an active position, the lever L may be returned toward its former governing position only so far as to break the circuit for the power applied when in the new governing position. A predetermined time after the power current ceases to flow, the locking member 25 assumes an inactive position so that the control lever L may be returner to its former governing position. Thus, the lever L is prevented from being quickly returned from a new governing posiion to the former governing position.

It is believed that the usefulness and operation of such a system will be more readily understood by further description being given from the standpoint of operation of the interlocking system taken as a whole.

Operation 0; the system @Vith the apparatus and the circuits of the interlocking system in the normal condition as shown, the contact 22 of the SS relay is in a right hand energized position, as the local winding 20 is continuously energized from the secondary of transformer T and the line phase winding 21 is energized over a normal circuit completed with the track s ritch TS and the switch machine SM in a normal locked condition.

The normal energizing circuit for the line phase winding 21 of the SS relay is traced as follows :--froin the right hand terminal of the secondary of transformer T, through wires and 31, contacts 832, wires 33, 3d and 35, line phase winding 21 of the SS relay, wires 36 and 37, contacts 9'38, wires 39 and L0, to the left hand terminal of the secondary of transformer T. 1

Let us assume that the operator desires to reverse the track switch TS, and to do so presses the lever latch 2 L preparatory to moving the lever L in a left hand direction This operation closes an energizing circuit through contact 23 for energizing the indication magnet 15 through a circuit traced as follows :-from the positive terminal of a suitable source of electrical potential indicated as 13+, through contact 22 in a right hand position, wire 42, contacts 14:4:3, wires 44 and 45, windings of indication magnet 15, wire L6, closed contact 23, to the negative terminal of the suitable source indicated as B.

Assuming the detector track section associated with the track switch TS to be unoccupied, the associated lever look (not shown) will also be energized at this time, and the lever L may be moved to the new governing position RI. hen such movement is made, the circuit for the energization of the indication magnet 15 is opened at the contacts 1.4 43 as soon as the lever L leaves the position NI. Also, the plunger 16 is caused to assume an active locking posit-ion by a proj cction 47, so that the lever L can not be moved beyond the position RI.

With the lever L in the reverse indicating position R1, the reverse operating circuit for the switch machine SM is completed by the movable contact 12 so that power operating current flows from the positive terminal. of the battery BT through wire 50, the windings 51 of the power lock PL, wire 52, fuse F, wire 53, contacts 12-54, wires and 6, through the operating circuits of the switch machine SM to operate the switch machine motor, through the common wire C to the negative terminal of battery BT. Current flowing in this circuit operates the switch machine in the usual well known manner which is more specifically discussed in my above mentioned l atent No. 1,486,908.

This operating current of the switch machine SM operates the locking member 25 of the power lock PL to an active locking position so that should the lever L be quickly re turned in a di ection towards its former governing position NT, a projection 48 on the lever L would be engaged to prevent movement further than to permit the movable contact 20 to break the power operating circult just traced. However, after the power current is broken, the locking member 25 slowly release;--: so that the lever L may be returned to i s former governing position NI after predetermined period of time.

Assuming t 1e lever L to remain in the position RT and the switch machine SM to operate, the contact block 7 is operated to an in termediate position as soon as the track s vitch TS is unlocked which causes the contact 22 to assume an intermediate position as its energizing circuit is broken at the contacts 832 and 9-38. Also, the shunt contacts 10 and 11 assume tiieir biased cortacting positions, 00:. ting a shunt path from wire 35, through shunt contact 10, wire shunt contact 11, to the wire 86, which path shunts out all foreign currents.

hen the switch machine SM has operated the track switch TS to a reverse locked condition, the movable contact block 7 is operated to a reverse extreme position and the shunt contact 11 is actuated to a. non-contacting position. Thus, a reverse energizcircuit for the line-phase winding 21 for the SS relay is es ablisied through a circuit traced as follows :from the right hand ter' minal of the secondary of transformer T, through wire 30, contacts 9 i wires 5'? and winding 21 of the SS relay, wires 35, 8d and 58, contacts 8 59, wire i0, to the left hand terminal of the secondary of transformer T.

lVith the reverse energizing circuit for the line-phase winding 21 of relay SS completed, the contact 22 is caused to assume a left hand energized position, in which posie preliminary unlocking per tion a circuit is completed for energizing the indication magnet of the indication latch mechanism 1M, when the lever latch 24 is actuated to close the contact 23. This energizing circuit for releasing the indication latch mechanism 1M is traced as follows from the positive terminal of a suitable source of electrical potential indicated as 13+, through contact 22 in a left hand position, wire 60, contacts l l61, wires 62 and 5, windings of indication magnet 15, wire 46. closd contact 23, to the erminal of the suitable source indicated as B. The lever L may now be moved to the position it.

The operation of the interlocking system shown as a specific embodiment of the present invention, has been described from the normal condition to the reverse condition, which is considered sufhcient to point out the characteristic features of the present invention. The operation of the system from the reverse condition to the normal condition is merely an inverse function of the operation above described.

There is a period of time after power is applied to the switch machine motor during u l...-ch said switch ma ne motor op unlock the track sw o S at this 7 rod of time, the point detector contacts PD remain in a position in correspondence with the track switch TS and its locked condition, thus the contact of the relay indicates in the tower tlrt the track switch :s in a certain position and locked during the time that the switch machine motor is operating to unlock the track switch.

lVithout the power lock PL the possibility arises the control lever L may be moved from the position l l to the position RI and then quickly returned to the position NI before the track switch TS becomes unlocked. With the lever L in the position N1 and the contact 22 of tne relay SS in a normal position the indication latch mechanism 1M may be actuated to a released condition so that the lever L can be returned t its full position N. However, during the time that the control lever L we in the position lll, the switch machine SM may receive suiiicient power to give it momentum which will carry it beyond the unlocked condition of the track switch TS, so that should the fuse F blow out when the reversal of current upon the switch machine ing systems and filed of even date herewith.

A contingency, as above pointed out, is unsafe and fully provided for by the provision of the power lock PL which prevents the quick reversal of the lever L while power current is supplied to the switch machine and durin g a predetermined time thereafter. The slow releasing period of the lock PL is of such duration of time as to prevent the lever L from being returned to a former position until the switch machine has had time to spend such momentum as it may have gained. In other words, the period of time should be slightly greater than that which is consumed by the switch machine in unlocking the track switch TS.

Such an interlocking system has the ad vantage that the initiation of the switch mahine movement is indicated in the tower, so that the control lever L may be governed in accordance therewith. An additional desirable feature is that the control lever L may be returned to a former full position, at any such time that the SS relay indicates the associated track switch TS to be in a particular extreme position and locked. In other words. should the control lever L be moved ing position and the switch ii for some reason to operate, lrn the control lever L could be returned to its former full normal position, allowing echanical interlocking between levers to be re leased in a manner to permit other routes to ov up including the track switch TS in its particular position 1nd1cated by the SS relay ()ne specific constr ction of devices and arrangement of circuits has been shown as an enuiodiment of the interlocking system accl rding to the present invention; however, it

ES to e understood that the various devices an d circuit arrangements selected are to facllit i the disclosure of the nature of the V on rat 1er than its specific form, and it is t be further understood that various modifications and adaptations may be made without departing from the spirit or scope of the invention as demanded by the following claims.

Having described my invention, I now slain 1. In an interlocking system, a track switch controlled by a switch machine, a control lever located in a tower and governing said switch machine, and means prej quick moven'ient of said control lever er governing position during opersaid switch machine.

2. In an interlocking system, a track 1 controlled by a switch machine, a ol lever located in a tower and governing the movement of said switch machine,

near-s preventing rapid reversal of said control lever to a former governing position during the unlocking of said track switch by said witch machine.

3. In an interlocking system, a track switch controlled by a switch machine, a control lever located in the tower and governing the movement o1 said switch machine, locking means preventing certain movements of said control lever by use of the operatin currentof said switch machine for actuating said locking means.

l. In an interlocking system, a track h controlled by a switch machine, a co 01 I318!) located in a tower and governing the movement of said switch machine, and means active to prevent said control lever from movement from a new governing posit" to a former governing position until current for said switch. machine has ceased flowing for a predetermined period of time.

5. In an interlocking system, a track switch operated by a switch machine, a control lever located in a tower and governing the operation of said switch machine, locking means governing the movement of said control lever, said locking means including, a member normally inactive, energizing windings for actuating said locking memberto an active position, a locking bar controlled by said control lever and detained from certain movements with said locking member in an active position, and energizing circuits for said energizing windings including the normal and reverse operating circuits of said switch machine.

6. In an interlocking system for railroads, a switch machine, a control lever for governing said switch machine, and means governing reversal of said lever only during operation of said switch machine.

7. In an interlocking system for railroads, switch machine, a control lever, operating circuits for said switch machine governed by said control lever, a detent on saidlever, a lock plunger for engaging said detent only when actuated, and electro-magnetic means for actuating said lock plunger. said means having windings included in said operating circuits.

8. In combination, an operated device, m s for operating said device, a control le governing said operating means, indication means responsive to the condition of said operated device for governing operation of said control lever, and time measuring means retarding operation of said control lever for a predetermined time only when said operating means has been governed thereby providing a time delay to compe -isate for tardy response of said indication means.

9. In combination, one operated device, means for operating said one device, a control lever for governing said operating neans. indication means responsive to the condition of said one device. another operated device governed in accordance with said 5 control lever and said indication means, and

time measuring means retarding operation of said control lever from a new governing position to a former governing position for providing a time delay to compensate for tardy response of said indication. means, whereby said another device cannot be improperly governed.

10. In combination, a controlled device, a lever for controlling said device, locking means preventing movement of said lever from a particularintermediate position to a corresponding extreme position except when actuated, indication means capable of actuating said locking means when said lever is in correspondence with said device, and a time delayed lock for restraining movement of said lever, whereby movement of said lever is delayed for a time suificient to compensate for the tardy response of said indication means to thereby prevent said locking means from being improperly actuated.

11. In an interlocking system for railroads, a track switch, a switch machine, a control lever, operating circuits for said switch machine governed by said control lever, an indication latch mechanism preventing movement of said control lever from a particular intermediate position to a corresponding extreme position, indication means capable of actuating said indication latch mechanism to release said control lever when said track switch and said control lever are in correspondence, a detent on said lever, a. lock plunger for engaging said detent when actuated, and electro-magnetic means for actuating said lock plunger, said means having windings included in said operating circuits, whereby said indication latch mechanism may not be improperly actuated to release said control lever.

12. In an interlocking system for railroads, a track switch, a switch machine for operating said track switch, a control lever having two intermediate positions and two corresponding extreme positions, operating circuits for said switch machine governed by said control lever, an indication latch mechanism preventing movement of said control lever from a particular intermediate position to a corresponding extreme position, indication means capable of actuating said indication latch mechanism to release said control lever when said track switch and said control lever are in correspondence, a power lock for preventing movement of said control lever from one to the other of its said two intermediate positions when actuated, and electro-magnetic means for actuating said power lock, said electro-magnetic means having windings included in said operating circuits of said switch machine.

13. In an interlocking system for railroads, a power-operated switch machine having normal and reverse opera-ting circuits, a control lever having normal and reverse extreme positions and normal and reverse indication positions, contacts operated by said control lever, said contacts closing said normal operating circuits when said lever is in corresponding normal extreme and indication positions and closing-said reverse operating circuits when said lever is in corresponding reverse extreme and indication positions, a detent on said control lever, a lock plunger for engaging said detent when actuated to thereby prevent movement of said control lever from one to the other of its indication positions but permitting the opening of said operating circuits, and electro magnetic means for actuating said lock plunger, said electromagnetic means having windings included in said normal and reverse operating circuits.

14. In an interlocking system for railroads, a power-operated switch machine having normal and reverse operating circuits, a control lever having normal and reverse governing positions, contacts operated by said control lever, said contacts closing said normal operating circuit when said control lever is in a corresponding normal governing position and closing said reverse operating circuit when said control lever is in a corresponding reverse governing position, a detent on said control lever, lock plnniz'er for engaging said detent when actuated for preventing movement of said control lever from one to the other of said governing positions but permitting; the opening of saidoperating' circuits, and electromagnetic means for actuating said lock plunger, said electro-man netic means having windings included in said normal and reverse operating circuits.

In testimony whereof I affir: my signature.

WINTER-OP K1 HOWE. 

